title: Adjusting for multiple-misclassified variables in a study using birth certificates.
abstract: OBJECTIVE
  Birth certificates are a convenient source of population data for epidemiologic studies. It is well documented, however, that birth certificate data can be highly inaccurate. Nonetheless, studies based on birth certificates are routinely analyzed without accounting for sources of data errors. We focused on the association between maternal cigarette smoking and cleft lip and palate based on birth certificate data.
  
  
  METHODS
  We adjusted odds ratio estimates simultaneously for exposure and outcome misclassification. We also calculated odds ratios adjusted for exposure misclassification only and outcome misclassification only.
  
  
  RESULTS
  Adjustment for both maternal smoking during pregnancy and clefting resulted in adjusted odds ratios that ranged from less than 1.0 to much greater than the unadjusted estimate of 1.16, with most adjusted estimates outside of the 95% confidence limits (1.01, 1.33).
  
  
  CONCLUSIONS
  Because of the potentially large impact of birth certificate classification errors, we suggest that inferences from these or similar records employ quantitative methods for incorporating uncertainties caused by data errors.
authors.affiliation: Center for Healthcare Research & Innovation, Allina Health, Minneapolis, MN 55407, USA. jure0007@umn.edu
authors.forename: Anne M
authors.initials: AM
authors.lastname: Jurek
authors.forename: Sander
authors.initials: S
authors.lastname: Greenland
mesh_terms: D015982:Bias; D001719:Birth Certificates; D002971:Cleft Lip / Q000453:epidemiology / Q000209:etiology; D002972:Cleft Palate / Q000453:epidemiology / Q000209:etiology; D005260:Female; D006801:Humans; D015233:Models, Statistical; D016017:Odds Ratio; D011247:Pregnancy; D011248:Pregnancy Complications; D012907:Smoking / Q000009:adverse effects; D014481:United States / Q000453:epidemiology
keywords: Bias; Birth certificates; Cigarette smoking; Cleft lip and palate; Misclassification; Sensitivity analysis; Sensitivity and specificity